When fused to the transcription activation domain of Gal4p, the carboxy terminal domain of Tcn1p directed strong calcineurin-independent expression of PMC1-lacZ and other target genes. The amino-terminal domain of Tcn1p was found to function as a calcineurin-dependent transcription activation domain when fused to the DNA-binding domain of Gal4p. This amino-terminal domain also formed Ca 2+-dependent and FK506-sensitive interactions with calcineurin in the yeast two-hybrid assay. These findings suggest that Tcn1p functions as a calcineurin-dependent transcription factor. Interestingly, induction of Tcn1p-dependent genes was found to be differentially controlled in response to physiological Ca 2+ signals generated by treatment with mating pheromone and high salt. We propose that different promoters are sensitive to variations in the strength of Ca 2+ signals generated by these stimuli and to effects of other signaling pathways.